Lighting module

ABSTRACT

A lighting module may be provided that includes a light guide plate; a first case coupled to one side of the light guide plate; a first light source which is disposed in the first case and emits light to the one side of the light guide plate; a second case coupled to the other side of the light guide plate; and a second light source which is disposed in the second case and emits light to the other side of the light guide plate. An amount of light which is emitted through a top surface of the light guide plate is equal to or not equal to an amount of light which is emitted through a bottom surface of the light guide plate.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C. §119(e) of Korean Patent Application No. 10-2010-0131152 filed Dec. 21, 2010, No. 10-2011-0040184 filed Apr. 28, 2011, No. 10-2011-0050542 filed May 27, 2011, the subject matters of which are incorporated herein by reference.

BACKGROUND

1. Field

Embodiments may relate to a lighting module.

2. Background

A light emitting diode (LED) is an energy device for converting electric energy into light energy. Compared with an electric bulb, the LED has higher conversion efficiency, lower power consumption and a longer life span. As there advantages are widely known, more and more attentions are now paid to a lighting apparatus using the LED.

The lighting apparatus using the LED are generally classified into a direct lighting apparatus and an indirect lighting apparatus. The direct lighting apparatus emits light emitted from the LED without changing the path of the light. The indirect lighting apparatus emits light emitted from the LED by changing the path of the light through reflecting means and so on. Compared with the direct lighting apparatus, the indirect lighting apparatus mitigates to some degree the intensified light emitted from the LED and protects the eyes of users.

SUMMARY

One embodiment is a lighting module. The lighting module includes a light guide plate; a first case coupled to one side of the light guide plate; a first light source which is disposed in the first case and emits light to the one side of the light guide plate; a second case coupled to the other side of the light guide plate; and a second light source which is disposed in the second case and emits light to the other side of the light guide plate. An amount of light which is emitted through a top surface of the light guide plate is equal to or not equal to an amount of light which is emitted through a bottom surface of the light guide plate.

Another embodiment is a lighting module. The lighting module includes a first light guide plate; a second light guide plate disposed below the first light guide plate; a reflective plate between the first light guide plate and the second light guide plate; a first and a second light sources which are disposed on both sides of the first light guide plate respectively; a third and a fourth light sources which are disposed on both sides of the second light guide plate respectively; a first case coupled to one side of the first light guide plate and to one side of the second light guide plate; and a second case coupled to the other side of the first light guide plate and to the other side of the second light guide plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Arrangements and embodiments may be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein:

FIG. 1 is a perspective view of a lighting module according to an embodiment;

FIG. 2 is a cross sectional view of the lighting module according to the embodiment;

FIG. 3 is a perspective view of a first case and a second case shown in FIG. 1;

FIG. 4 is a cross sectional view of a lighting module according to another embodiment;

FIG. 5 is a perspective view of a lighting module according to further another embodiment;

FIG. 6 is a cross sectional view of the lighting module shown in FIG. 5;

FIG. 7 is an exploded perspective view of the lighting module shown in FIG. 5;

FIG. 8 is a view for describing how a first case 200 a″ of the lighting module shown in FIG. 5 is coupled to a first and a second light guide plates 110 a and 110 b of the lighting module shown in FIG. 5;

FIG. 9 is a cross sectional view of a lighting module according to still another embodiment;

FIG. 10 is a view showing the light distribution characteristic of the lighting module shown in FIG. 9;

FIG. 11 is a view showing a lighting module according to still another embodiment and a light distribution characteristic of the lighting module;

FIG. 12 is a cross sectional view of a lighting module according to still another embodiment.

DETAILED DESCRIPTION

A thickness or a size of each layer may be magnified, omitted or schematically shown for the purpose of convenience and clearness of description. The size of each component may not necessarily mean its actual size.

It should be understood that when an element is referred to as being ‘on’ or “under” another element, it may be directly on/under the element, and/or one or more intervening elements may also be present. When an element is referred to as being ‘on’ or ‘under’, ‘under the element’ as well as ‘on the element’ may be included based on the element.

An embodiment may be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a lighting module according to an embodiment. FIG. 2 is a cross sectional view of the lighting module according to the embodiment.

Referring to FIGS. 1 and 2, a lighting module 100 according to an embodiment may include a first case 200 a, a second case 200 b, a first light source 150 a, a second light source 150 b, a first phosphor luminescent film 170 a (hereafter, referred to as PLF), a second phosphor luminescent film 170 b, a light guide plate 110 and diffuser plates 130 a and 130 b.

The first case 200 a and the second case 200 b may be manufactured by extrusion molding one plate. The first case 200 a and the second case 200 b may be formed by bending twice one plate. Also, the first case 200 a and the second case 200 b may include a seating portion by bending twice one plate. Specifically, this will be described with reference to FIG. 3.

FIG. 3 is a perspective view of the first and the second cases shown in FIG. 1.

Referring to FIGS. 1 to 3, the first case 200 a may include a first seating portion 202 a in which the first light source 150 a may be disposed. The second case 200 b may include a second seating portion 202 b in which the second light source 150 b may be disposed.

The first case 200 a includes a base 210 a and a flange 230 a. The first light source 150 a is disposed in the base 210 a. The flange 230 a extends in a perpendicular direction from both side ends of the base 210 a. The second case 200 b includes a base 210 b and a flange 230 b. The second light source 150 b is disposed in the base 210 b. The flange 230 b extends in a perpendicular direction from both side ends of the base 210 b. The first and the second seating portions 202 a and 202 b may be formed by the bases 210 a and 210 b and the flanges 230 a and 230 b of the first and the second cases 200 a and 200 b.

The first and the second seating portions 202 a and 202 b may receive not only the first and the second light sources 150 a and 150 b but also a portion of the light guide plate 110. Specifically, one side of the light guide plate 110 is inserted into the first seating portion 202 a. The other side of the light guide plate 110 is inserted into the second seating portion 202 b.

The flanges 230 a and 230 b of the first and the second cases 200 a and 200 b may include projections 230 a-1 and 230 b-1. The projections 230 a-1 and 230 b-1 may extend outward from the flanges 230 a and 230 b. The projections 230 a-1 and 230 b-1 are able to limit the movement of the light guide plate 110 which is received in the first and the second seating portions 202 a and 202 b. Also, the projections 230 a-1 and 230 b-1 are able to prevent the light guide plate 110 from separating from the first and the second cases 200 a and 200 b.

It is recommended that the first and the second cases 200 a and 200 b should be made of a metallic material such as aluminum, an alloy including aluminum and iron and the like. Also, the first and the second cases 200 a and 200 b may have a predetermined elastic force.

The first case 200 a has a consistent cross section in a longitudinal direction thereof. The second case 200 b has a consistent cross section in a longitudinal direction thereof.

Referring back to FIGS. 1 to 2, the first and the second light sources 150 a and 150 b respectively include substrates 151 a and 151 b and light emitting devices 152 a and 152 b disposed on the substrates.

The substrate 151 a of the first light source 150 a and the substrate 151 b of the second light source 150 b are arranged to face each other. The light emitting device 152 a of the first light source 150 a and the light emitting device 152 b of the second light source 150 b are arranged to face each other. The substrate 151 a and the light emitting device 152 a of the first light source 150 a are disposed in the first seating portion 202 a of the first case 200 a. The substrate 151 b and the light emitting device 152 b of the second light source 150 b are disposed in the second seating portion 202 b of the second case 200 b.

The substrates 151 a and 151 b may be a printed circuit board (PCB), a metal core PCB (MCPCB), a flexible PCB (FPCB) or a ceramic substrate or the like.

The light emitting device 152 a of the first light source 150 a and the light emitting device 152 b of the second light source 150 b may emit white light having the same color temperature or may emit white lights having mutually different color temperatures. Here, when the light emitting device 152 a of the first light source 150 a and the light emitting device 152 b of the second light source 150 b emit lights having mutually different color temperatures, various color senses can be expressed through a combination of the two different color temperatures. Accordingly, emotional lighting can be created and a color rendering index (CRI) can be improved. As a result, it is possible to prevent an actual color of an object from being distorted and to reduce the fatigue of the eyes of users. For example, the light emitting device 152 a of the first light source 150 a may be a warm white light emitting device and the light emitting device 152 b of the second light source 150 b may be a cool white light emitting device.

The light emitting devices 152 a and 152 b may be a light emitting diode (hereinafter, referred to as LED). Here, the LED may emit one of blue light, red light and green light. The light emitting devices 152 a and 152 b may be a lateral type LED or a vertical type LED.

The light emitting devices 152 a and 152 b may include a fluorescent material. For example, when the light emitting devices 152 a and 152 b are a LED chip emitting blue light, the light emitting devices 152 a and 152 b may include a resin which covers the LED chip and includes the fluorescent material. The fluorescent material may be at least one of a garnet based fluorescent material (YAG, TAG), a silicate based fluorescent material, a nitride based fluorescent material and anoxynitride based fluorescent material.

While the light emitting devices 152 a and 152 b may be formed to emit natural light (white light) by using a yellow fluorescent material, the light emitting devices 152 a and 152 b may further include a green fluorescent material or a red fluorescent material in order to improve the color rendering index and to reduce the color temperature. Here, when various kinds of the fluorescent materials are mixed in the resin, the green fluorescent material may be more used than the red fluorescent material, and the yellow fluorescent material may be more used than the green fluorescent material.

The yellow fluorescent material may be YAG of the garnet based fluorescent material, a silicate based fluorescent material and an oxynitride based fluorescent material. The red fluorescent material may be a silicate based fluorescent material and an oxynitride based fluorescent material. The red fluorescent material may be a nitride based fluorescent material.

The resin may be composed of a first resin including the red fluorescent material, a second resin including the green fluorescent material and a third resin including the yellow fluorescent material as well as may be composed of various kinds of the fluorescent materials mixed therein. The light guide plate 110 is disposed between the first light source 150 a and the second light source 150 b.

The light guide plate 110 may have a plate shape having four sides, a top surface and a bottom surface.

The first light source 150 a is disposed on one side of the light guide plate 110. The second light source 150 b is disposed on the other side opposite to the one side of the light guide plate 110.

The light guide plate 110 is coupled to the first and the second cases 200 a and 200 b. Specifically, one side of the light guide plate 110 is inserted into the first seating portion 202 a of the first case 200 a. The other side of the light guide plate 110 is inserted into the second seating portion 202 b of the second case 200 b.

Light is incident on two sides of the light guide plate 110 and is emitted through the top and the bottom surfaces of the light guide plate 110. Specifically, the light guide plate 110 receives the light through the two sides thereof from the first and the second light sources 150 a and 150 b, and emits the received light outward through the top and the bottom surfaces.

The material of the of the light guide plate 110 may be any one of polyethylene terephthlate (PET), poly carbonate (PC), cycloolefin copolymer (COC) and polyethylene naphthalate (PEN) and an acrylic resin like polymethylmetaacrylate (PMMA) in consideration of thermal expansion depending on a temperature in use of the material.

The first phosphor luminescent film 170 a may be disposed between the light guide plate 110 and the first light source 150 a. The second phosphor luminescent film 170 b may be disposed between the light guide plate 110 and the second light source 150 b.

The first and the second phosphor luminescent films 170 a and 170 b may include a fluorescent material. The first and the second phosphor luminescent films 170 a and 170 b are excited by the light emitted from the first and the second light sources 150 a and 150 b and are able to emit light with a wavelength different from that of the light emitted from the first and the second light sources 150 a and 150 b. The light emitted from the first and the second light sources 150 a and 150 b is mixed with the light emitted from the first and the second phosphor luminescent films 170 a and 170 b, so that white light can be created.

The first and the second phosphor luminescent films 170 a and 170 b may include a transparent resin and a fluorescent material contained within the transparent resin. The transparent resin may include a curing agent or an additive. The curing agent cures the transparent resin. The additive uniformly disperses the fluorescent material within the transparent resin. The transparent resin may include a diffusion material. The diffusion material is able to improve an excitation ratio of the fluorescent material by improving the refraction of light.

A first diffuser plate 130 a and a second diffuser plate 130 b diffuse light which is emitted from the light guide plate 110. The first and the second diffuser plates 130 a and 130 b can remove a hot spot which may be generated in the light guide plate 110.

The first diffuser plate 130 a may be disposed on the top surface of the light guide plate 110. The second diffuser plate 130 b may be disposed on the bottom surface of the light guide plate 110.

Both sides of the first diffuser plate 130 a and both sides of the second diffuser plate 130 b may be disposed within the first and the second cases 200 a and 200 b. Specifically, both sides of the first diffuser plate 130 a and both sides of the second diffuser plate 130 b may be inserted into the first seating portion 202 a of the first case 200 a and the second seating portion 202 b of the second case 200 b.

Meanwhile, the first and the second diffuser plates 130 a and 130 b may be disposed on any one surface of the top and the bottom surfaces of the light guide plate 110. A reflective plate (not shown) may be disposed on the other surface. That is, the first diffuser plate 130 a may be replaced by the reflective plate. In this case, since the first diffuser plate 130 a reflects all of the light which is emitted from the bottom surface of the light guide plate 110, the light is emitted through the top surface of the light guide plate 110 and the second diffuser plate 130 b.

The lighting module shown in FIGS. 1 to 2 is able to irradiate light in one direction and is also able to irradiate light not only in one direction but also in a direction symmetrical to the one direction at the same time.

FIG. 4 is a cross sectional view of a lighting module according to another embodiment.

The lighting module shown in FIG. 4 includes the lighting module shown in FIGS. 1 to 3. Therefore, in description of the lighting module shown in FIG. 4, the same reference numerals are assigned to the same elements as those of the lighting module shown in FIGS. 1 to 3. Detailed descriptions of the same elements will be omitted.

The lighting module shown in FIG. 4 may include a first and a second cases 200 a′ and 200 b′, a first to a fourth light sources 150 a, 150 b, 150 c and 150 d, a first and a second light guide plates 110 a and 110 b, a first and a second diffuser plates 130 a and 130 b, a first to a fourth phosphor luminescent films 170 a, 170 b, 170 c and 170 d and a reflective plate 190.

The first case 200 a′ receives the first and the third light sources 150 a and 150 c and receives one sides of the first and the second light guide plates 110 a and 110 b. The second case 200 b′ receives the second and the fourth light sources 150 b and 150 d and receives the other sides of the first and the second light guide plates 110 a and 110 b.

The first and the third light sources 150 a and 150 c are received in the first case 200 a′ and disposed separately from each other in the first case 200 a′. The first light source 150 a emits light to one side of the first light guide plate 110 a. The third light source 150 c emits light to one side of the second light guide plate 110 b. The first phosphor luminescent film 170 a may be disposed between the first light source 150 a and the first light guide plate 110 a, that is, on the one side of the first light guide plate 110 a. The third phosphor luminescent film 170 c may be disposed between the third light source 150 c and the second light guide plate 110 b, that is, on the one side of the second light guide plate 110 b.

The second and the fourth light sources 150 b and 150 d are received in the second case 200 b′ and disposed separately from each other in the second case 200 b′. The second light source 150 b emits light to the other side of the first light guide plate 110 a. The fourth light source 150 d emits light to the other side of the second light guide plate 110 b. The second phosphor luminescent film 170 b may be disposed between the second light source 150 b and the first light guide plate 110 a, that is, on the other side of the first light guide plate 110 a. The fourth phosphor luminescent film 170 d may be disposed between the fourth light source 150 d and the second light guide plate 110 b, that is, on the other side of the second light guide plate 110 b.

The first light guide plate 110 a is disposed between the first light source 150 a and the second light source 150 b. The second light guide plate 110 b is disposed between the third light source 150 c and the fourth light source 150 d.

The second light guide plate 110 b is disposed below the first light guide plate 110 a. Specifically, the bottom surface of the first light guide plate 110 a is disposed above the top surface of the second light guide plate 110 b.

The reflective plate 190 may be disposed between the first light guide plate 110 a and the second light guide plate 110 b. One side of the reflective plate 190 may be disposed contacting with the bottom surface of the first light guide plate 110 a. The other side the reflective plate 190 may be disposed contacting with the top surface of the second light guide plate 110 b. Micro lenses may be arranged on both sides of the reflective plate 190 in the form of an array.

Light emitted from the first light source 150 a and the second light source 150 b is incident on both sides of the first light guide plate 110 a and travels along an optical path within the first light guide plate 110 a. A part of the light traveling within the first light guide plate 110 a is directly emitted through the top surface of the first light guide plate 110 a. The rest of the light is reflected by the reflective plate 190 and is emitted through the top surface of the first light guide plate 110 a.

Light emitted from the third light source 150 c and the fourth light source 150 d is incident on both sides of the second light guide plate 110 b and travels along an optical path within the second light guide plate 110 b. A part of the light traveling within the second light guide plate 110 b is directly emitted through the bottom surface of the second light guide plate 110 b. The rest of the light is reflected by the reflective plate 190 and is emitted through the bottom surface of the second light guide plate 110 b.

The first diffuser plate 130 a may be disposed on the bottom surface of the second light guide plate 110 b. The second diffuser plate 130 b may be disposed on the top surface of the first light guide plate 110 a.

Meanwhile, positions of the first diffuser plate 130 a and the reflective plate 190 may be changed. In other words, the first diffuser plate 130 a may be disposed between the first light guide plate 110 a and the second light guide plate 110 b, and the reflective plate 190 may be disposed on the bottom surface of the second light guide plate 110 b. In this case, the lighting module according to the embodiment is able to emit light only through the top surface of the first light guide plate 110 a.

An amount of the light which is emitted from the top surface of the first light guide plate 110 a may be equal to or not equal to an amount of the light which is emitted from the bottom surface of the second light guide plate 110 b. Here, when the material of the first light guide plate 110 a is different from the material of the second light guide plate 110 b, the amount of the light which is emitted from the first light guide plate 110 a may be different from the amount of the light which is emitted from the second light guide plate 110 b.

Color temperatures of the light emitting device 152 a of the first light source 150 a, the light emitting device 152 b of the second light source 150 b, the light emitting device 152 c of the third light source 150 c and the light emitting device 152 d of the fourth light source 150 d may be different from one another. For example, the light emitting device 152 a of the first light source 150 a and the light emitting device 152 b of the second light source 150 b may be warm white LEDs. The light emitting device 152 c of the third light source 150 c and the light emitting device 152 d of the fourth light source 150 d may be cool white LEDs.

The reflective plate 190 has a rectangular plate shape corresponding to the shapes of the first light guide plate 110 a and the second light guide plate 110 b. The reflective plate 190 may be formed of a flexible plastic material.

Both entire surfaces of the reflective plate 190 may be coated with a reflective material. Additionally, the reflective material may be coated only on surfaces of portions which correspond to actual light emitting areas of the first and the second diffuser plates 130 a and 130 b.

Reflectances of the reflective materials coated on the both surfaces of the reflective plate 190 may not be equal to each other. Accordingly, it is possible to cause the amounts of the lights emitted from the first and the second light guide plates 110 a and 110 b to be different from each other.

A lens array is disposed on both sides of the reflective plate 190. The amounts of the lights emitted from the first and the second light guide plates 110 a and 110 b can be different from each other by causing an interval between adjacent lenses in the lens array disposed on one side to be different from an interval between adjacent lenses in the lens array disposed on the other side.

The reflective plate 190 is disposed between the first and the second light guide plates 110 a and 110 b. The reflective plate 190 prevents the light emitted from the first and the second light sources 150 a and 150 b from being incident on the second light guide plate 110 b, and prevents the light emitted from the third and the fourth light sources 150 c and 150 d from being incident on the first light guide plate 110 a.

FIG. 5 is a perspective view of a lighting module according to further another embodiment. FIG. 6 is a cross sectional view of the lighting module shown in FIG. 5. FIG. 7 is an exploded perspective view of the lighting module shown in FIG. 5.

Referring to FIGS. 5 to 7, the lighting module according to the embodiment is similar to the lighting module shown in FIG. 4. Therefore, in description of the lighting module shown in FIGS. 5 to 7, the same reference numerals are assigned to the same elements as those of the lighting module shown in FIG. 4. Detailed descriptions of the same elements will be omitted.

The lighting module shown in FIGS. 5 to 7 includes a first case 200 a″, a second case 200 b″, a first to a fourth light sources 150 a, 150 b, 150 c and 150 d, a first to a fourth phosphor luminescent films 170 a, 170 b, 170 c and 170 d, a first and a second light guide plates 110 a and 110 b and a reflective plate 190.

The first case 200 a″ receives the first and the third light sources 150 a and 150 c and covers one sides of the first and the second light guide plates 110 a and 110 b. The second case 200 b″ receives the second and the fourth light sources 150 b and 150 d and covers the other sides of the first and the second light guide plates 110 a and 110 b. Since the second case 200 b″ is the same as the first case 200 a″, a description of the second case 200 b″ is replaced by a description of the first case 200 a″.

The first case 200 a″ includes a lower case 210 a″ and an upper case 220 a″. The lower case 210 a″ and the upper case 220 a″ may be coupled to each other by a plurality of screws “S”.

The lower case 210 a″ includes a base 211 a″ and an extension part 212 a″. The first and the third light sources 150 a and 150 c are disposed on the inner surface of the base 211 a″. The extension part 212 a″ extends from one side edge of the inner surface of the base 211 a″ in a direction perpendicular to the inner surface. The extension part 212 a″ contacts with the bottom surface of the second light guide plate 110 b and supports the second light guide plate 110 b.

The upper case 220 a″ includes a base 221 a″ and an extension part 222 a″. The base 211 a″ of the lower case 210 a″ is disposed on the inner surface of the base 221 a″. The extension part 222 a″ extends from one side edge of the inner surface of the base 221 a″ in a direction perpendicular to the inner surface. The extension part 222 a″ contacts with the top surface of the first light guide plate 110 a and supports the first light guide plate 110 a.

Here, a length of the extension part 222 a″ of the upper case 220 a″ may be different from that of the extension part 212 a″ of the lower case 210 a″. For example, the length of the extension part 222 a″ of the upper case 220 a″ may be less than that of the extension part 212 a″ of the lower case 210 a″.

The base 211 a″ of the lower case 210 a″ may include a recess “g1”. The base 221 a″ of the upper case 220 a″ may include a hole “h1”. The hole “h1” corresponds to the recess “g1”. Therefore, when the lower case 210 a″ is coupled to the upper case 220 a″, the screw “S” passes through the hole “h1” and is inserted into the recess “g1”. As a result, the base 211 a″ of the lower case 210 a″ is fixed close to the base 221 a″ of the upper case 220 a″. Here, the base 211 a″ of the lower case 210 a″ includes the recess “g1” instead of the hole in order that the first and the third light sources 150 a and 150 c are prevented from being damaged or broken by the screw “S” and from being electrically contacted with the screw “S”.

The base 211 a″ of the lower case 210 a″ includes an opening G2. The base 221 a″ of the upper case 220 a″ includes an opening G1. The opening G2 of the lower case 210 a″ is disposed at a position corresponding to the opening G1 of the upper case 220 a″. Specifically, the opening G2 and the opening G1 may be disposed on one side of the first and the third light sources 150 a and 150 c, respectively. A driving driver 500 is disposed in the opening G2 of the lower case 210 a″ and the opening G1 of the upper case 220 a″. The driving driver 500 is electrically connected with the first and the third light sources 150 a and 150 c and supplies the first and the third light sources 150 a and 150 c with electric power from the outside. The driving driver 500 is also able to control the on/off of the first and the third light sources 150 a and 150 c.

Though not shown in the drawings, the extension part 212 a″ of the lower case 210 a″ may include a recess into which one side of a substrate 151 c of the third light source 150 c is inserted. The extension part 222 a″ of the upper case 220 a″ may include a recess into which one side of a substrate 151 a of the first light source 150 a is inserted.

The inner surface of the extension part 212 a″ of the lower case 210 a″ may include a receiving recess “r”. This will be described in detail with reference to FIG. 8.

FIG. 8 is a view for describing how the first case 200 a″ of the lighting module shown in FIG. 5 is coupled to the first and the second light guide plates 110 a and 110 b of the lighting module shown in FIG. 5.

Referring to FIG. 8, a protrusion 115 b formed on the bottom surface of the second light guide plate 110 b is inserted into the receiving recess “r” of the extension part 212 a″ of the lower case 210 a″. Therefore, a coupling force between the extension part 212 a″ of the lower case 210 a″ and the second light guide plate 110 b can be strengthened and the second light guide plate 110 b can be prevented from moving or separating. Here, the receiving recess “r” may be formed in the inner surface of the extension part 222 a″ of the upper case 220 a″. The protrusion 115 b may be formed on the top surface of the first light guide plate 110 a.

The base 211 a″ of the lower case 210 a″ and the extension part 212 a″ of the lower case 210 a″ may be independently formed. The lower case 210 a″ may be configured by coupling the base 211 a″ and the extension part 212 a″. The base 221 a″ of the upper case 220 a″ and the extension part 222 a″ of the upper case 220 a″ may be also independently formed. The upper case 220 a″ may be configured by coupling the base 221 a″ and the extension part 222 a″.

The upper case 220 a″ may include a receiving portion “R”. The receiving portion “R” receives one side of the first light source 150 a and one side of the base 211 a″ of the lower case 210 a″.

The first to the fourth light sources 150 a, 150 b, 150 c, and 150 d respectively include the substrates 151 a 151 b, 151 c, and 151 d and the light emitting devices 152 a, 152 b, 152 c and 152 d disposed on the substrates.

The first light source 150 a and the second light source 150 b are arranged to face each other. The first light guide plate 110 a is disposed between the first and the second light sources 150 a and 150 b. The third light source 150 c and the fourth light source 150 d are arranged to face each other. The second light guide plate 110 b is disposed between the third and the fourth light sources 150 c and 150 d.

The first light source 150 a and the third light source 150 c are disposed in the first case 200 a″. The second light source 150 b and the fourth light source 150 d are disposed in the second case 200 b″. The first light source 150 a and the third light source 150 c are disposed adjacent to or separately from each other in the first case 200 a″. The second light source 150 band the fourth light source 150 d are disposed adjacent to or separately from each other in the second case 200 b″.

Here, in the drawings, the substrate 151 a of the first light source 150 a is physically and electrically separated from the substrate 151 c of the third light source 150 c. However, the substrate 151 a of the first light source 150 a and the substrate 151 c of the third light source 150 c may be one substrate, and the light emitting device 152 a included in the first light source 150 a may be electrically separated from the light emitting device 152 c included in the third light source 150 c.

The light emitting devices included in the first and the second light sources 150 a and 150 b may emit light having the same color as that of light which is emitted from the light emitting devices included in the third and fourth light sources 150 c and 150 d or may emit light having a color different from that of light which is emitted from the light emitting devices included in the third and fourth light sources 150 c and 150 d. Therefore, light having various colors can be created through a combination of the two different colors and emotional lighting can be created.

The light emitting devices included in the first and the second light sources 150 a and 150 b may have different color temperature from that of the light emitting devices included in the third and fourth light sources 150 c and 150 d.

The light emitting devices 152 a, 152 b, 152 c and 152 d of the first to the fourth light sources 150 a, 150 b, 150 c and 150 d may be a blue light emitting device. However, the light emitting devices 152 a, 152 b, 152 c and 152 d may be a white light emitting device having a high color rendering index (CRI) if possible.

The light emitting device 152 a of the first light source 150 a and the light emitting device 152 b of the second light source 150 b may be warm white LEDs. The light emitting device 152 c of the third light source 150 c and the light emitting device 152 d of the fourth light source 150 d may be cool white LEDs.

The number of the light emitting devices 152 a and 152 b of the first and the second light sources 150 a and 150 b may be the same as or not the same as that of the light emitting devices 152 c and 152 d of the third and the fourth light sources 150 c and 150 d. When the number of the light emitting devices 152 a and 152 b of the first and the second light sources 150 a and 150 b is not the same as that of the light emitting devices 152 c and 152 d of the third and the fourth light sources 150 c and 150 d, an amount of the light which is emitted through the top surface of the first light guide plate 110 a may be different from an amount of the light which is emitted through the bottom surface of the second light guide plate 110 b. When the lighting module according to the embodiment is controlled such that the amount of the light which is emitted through the top surface of the lighting module is smaller than that of the light which is emitted through the bottom surface of the lighting module, the number of the light emitting devices 152 c and 152 d of the third and the fourth light sources 150 c and 150 d should be greater than that of the light emitting devices 152 a and 152 b of the first and the second light sources 150 a and 150 b.

The amounts of the lights which is emitted upward and downward from the lighting module according to the embodiment can be adjusted by varying values of currents applied to the first and the second light sources 150 a and 150 b and the third and the fourth light sources 150 c and 150 d. For example, in order that the amount of any one of the lights which is emitted upward and downward from the lighting module according to the embodiment is greater than that of the other, a value of a current applied to a light source emitting the light having the greater amount should be relatively increased.

The first light guide plate 110 a is optically coupled to the first and the second light sources 150 a and 150 b. The second light guide plate 110 b is optically coupled to the third and the fourth light sources 150 c and 150 d.

The second light guide plate 110 b is disposed below the first light guide plate 110 a.

One sides of the first and the second light guide plates 110 a and 110 b are received in the first case 200 a″. The other sides of the first and the second light guide plates 110 a and 110 b are received in the second case 200 b″.

One sides of the first and the second light guide plates 110 a and 110 b may include a coating film having a particular pattern or a roughness in order to allow the light incident into the inside of the first and the second light guide plates 110 a and 110 b to be emitted outward. The coating film having the particular pattern or the roughness diffuses or scatters the light, and then is able to control alight distribution characteristic of the light which is outwardly emitted.

Specifically, the first light guide plate 110 a has a first pattern “P1”. The second light guide plate 110 b has a second pattern “P2”. The first pattern “P1” may be disposed adjacent to the bottom surface of the first light guide plate 110 a. The second pattern “P2” may be disposed adjacent to the top surface of the second light guide plate 110 b. The first pattern “P1” and the second pattern “P2” may have the same shape or mutually different shapes. Here, though the first pattern “P1” and the second pattern “P2” have the same shape, the sizes of the patterns, intervals between the respective patterns or densities formed by the patterns may be different from each other.

The first pattern “P1” and the second pattern “P2” may include a plurality of dot patterns which are easy to form. The first pattern “P1” and the second pattern “P2” may include not only the dot pattern but also a pattern having a shape different from the dot pattern.

The first pattern “P1” and the second pattern “P2” may be formed by using an inkjet printing method or other various methods or may be formed when a plurality of lenses are formed on one sides of the first and the second light guide plates 110 a and 110 b or when the one sides themselves have a shape of a plurality of lenses. The lens has a size of a micro unit. The lens may be formed on entire one side surfaces of the first and the second light guide plates 110 a and 110 b or may be formed only on surfaces which correspond to actual light emitting areas of the first and the second light guide plates 110 a and 110 b.

The light distribution characteristic of the light which is emitted upward and downward from the lighting module can be controlled by differentiating the patterns formed on the one sides of the first and the second light guide plates 110 a and 110 b.

The reflective plate 190 is disposed between the first and the second light guide plates 110 a and 110 b. The reflective plate 190 prevents the light emitted from the first and the second light sources 150 a and 150 b from being incident on the second light guide plate 110 b, and prevents the light emitted from the third and the fourth light sources 150 c and 150 d from being incident on the first light guide plate 110 a.

The first phosphor luminescent film 170 a is disposed between the first light guide plate 110 a and the first light source 150 a. The second phosphor luminescent film 170 b is formed between the first light guide plate 110 a and the second light source 150 b. The third phosphor luminescent film 170 c is formed between the second light guide plate 110 b and the third light source 150 c. The fourth phosphor luminescent film 170 d is formed between the second light guide plate 110 b and the fourth light source 150 d.

The first to the fourth phosphor luminescent films 170 a to 170 d may include a fluorescent material. The first to the fourth phosphor luminescent films 170 a to 170 d change a portion of the wavelength of the light emitted from the first to the fourth light sources 150 a to 150 d and change the color of the light.

FIG. 9 is a cross sectional view of a lighting module according to still another embodiment.

Referring to FIG. 9, since a first and a second cases 200 a″ and 200 b″ are the same as the first and the second cases 200 a″ and 200 b″ of the lighting module shown in FIG. 5 and other portions not mentioned are the same as those of the lighting module shown in FIG. 5, descriptions thereabout will be omitted.

The first case 200 a″ receives one first light source 250 a. The second case 200 b″receives one second light source 250 b.

A first light guide plate 310 a becomes thinner the closer it is to one side from the other side of the first light guide plate 310 a. The first light guide plate 310 a becomes thinner the closer it is to the first light source 250 a from the second light source 250 b. A second light guide plate 310 b becomes thinner the closer it is to one side from the other side of the second light guide plate 310 b. The second light guide plate 210 a becomes thinner the closer it is to the second light source 250 b from the first light source 250 a.

The first light guide plate 310 a includes a first inclined surface. The second light guide plate 310 b includes a second inclined surface. The first inclined surface of the first light guide plate 310 a and the second inclined surface of the second light guide plate 310 b are disposed to face each other. A reflective plate 290 is disposed between the first inclined surface of the first light guide plate 310 a and the second inclined surface of the second light guide plate 310 b.

FIG. 10 is a view showing the light distribution characteristic of the lighting module shown in FIG. 9.

Referring to FIG. 10, the light distribution characteristic of the lighting module shown in FIG. 9 leans in one direction. This can occur when the first and the second light guide plates 210 a and 210 b have no predetermined pattern. The lighting module can be used in a spatial structure suitable for the light distribution characteristic. However, in general, the lighting module is necessary to have a Lambertian light distribution characteristic.

FIG. 11 is a view showing a lighting module according to still another embodiment and a light distribution characteristic of the lighting module.

The lighting module shown in FIG. 11 is formed by adding a first pattern “P1” to the first light guide plate of the lighting module of FIG. 10 and by adding a second pattern “P2” to the second light guide plate of the lighting module of FIG. 10. It can be seen that the light distribution characteristic of the lighting module shown in FIG. 11 does not lean in one direction due to the first pattern “P1” and the second pattern “P2”.

Referring to FIG. 11, the sizes, densities and shapes and the like of the first pattern “P1” and the second pattern “P2” may be or not the same as each other. Accordingly, even though the structures of the light guide plates become different from each other, the light which is emitted upward and downward from the lighting module is able to have a Lambertian light distribution characteristic. As a result, the lighting module can be substantially used more widely as a lighting device.

FIG. 12 is a cross sectional view of a lighting module according to still another embodiment.

Referring to FIG. 12, the structure of the lighting module shown in FIG. 12 is almost the same as the structure of the lighting module shown in FIG. 6.

A first and a second light sources 350 a and 350 b include substrates 351 a and 351 b and light emitting devices 352 a and 352 b. The light emitting device 352 a of the first light source 350 a is disposed on one side of a first light guide plate 110 a and emits light to the first light guide plate 110 a. The light emitting device 352 b of the second light source 350 b is disposed on one side of a second light guide plate 110 b and emits light to the second light guide plate 110 b.

The following Table 1 shows the specifications of the lighting modules shown in FIGS. 1 to 12.

TABLE 1 Product Item Value Strip Spec. Voltage(V) 39 (13S * 5P) Current(mA) 350 Power(W) 13.65 Module Total Lumen Up Lumen Output 2,500 2,000 Spec. output(lm) Down Lumen Output 500 Module Power(W) 27.3 Efficacy(lm/W) 90 CCT(K) 4,000 CRI 80 Fixture Spec. Lumen Output(lm) 10,000(Up: 8,000, Down: 2,000) DC Power Consumption(W) 110

Referring to Table 1, in the lighting modules shown in FIGS. 1 to 12, an up lumen output is greater than a down lumen output or may be less than the down lumen output. For example, a ratio of the up lumen output to the down lumen output maybe from 6:4 to 8:2.

Meanwhile, a value of width W (mm)×height H (mm)×length L (mm) of the lighting modules shown in FIGS. 1 to 12 may be either 80×12×560 or 45×12×560.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to affect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

What is claimed is:
 1. A lighting module comprising: a light guide plate; a first case coupled to one side of the light guide plate; a first light source which is disposed in the first case and emits light to the one side of the light guide plate; a second case coupled to the other side of the light guide plate; and a second light source which is disposed in the second case and emits light to the other side of the light guide plate wherein an amount of light which is emitted through a top surface of the light guide plate is equal to or not equal to an amount of light which is emitted through a bottom surface of the light guide plate, wherein the first case comprises a base in which the first light source is disposed, a first extension part extending from the base and a second extension part extending from the base, and wherein a length of the first extension part is less than a length of the second extension part.
 2. The lighting module of claim 1, wherein the first case comprises a flange which extends in a perpendicular direction from both side ends of the base and is connected to the light guide plate, wherein the flange includes a projection, and wherein the projection extends outwardly from one side of the flange and limits a movement of the light guide plate.
 3. The lighting module of claim 1, wherein the light guide plate comprises a top surface through which light is emitted and a bottom surface through which light is emitted, and further comprising a diffuser plate which is disposed on one of the top and the bottom surfaces of the light guide plate.
 4. The lighting module of claim 1, further comprising a phosphor luminescent film disposed between the first light source and the light guide plate.
 5. The lighting module of claim 1, wherein the light guide plate comprises a first light guide plate including a first inclined surface and comprises a second light guide plate including a second inclined surface disposed to face the first inclined surface, and further comprising a reflective plate disposed between the first inclined surface and the second inclined surface.
 6. The lighting module of claim 5, wherein the first inclined surface comprises a first pattern disposed adjacent to the reflective plate, wherein the second inclined surface comprises a second pattern disposed adjacent to the reflective plate, and wherein the first pattern and the second pattern have the same shape or mutually different shapes.
 7. The lighting module of claim 6, wherein the first pattern and the second pattern comprise a plurality of dot patterns, and wherein sizes of the first and the second patterns are different from each other or densities of the first and the second patterns are different from each other.
 8. The lighting module of claim 5, wherein values of currents applied to the first and the second light sources are different from each other, or wherein a number of light emitting devices included in the first light source is different from a number of light emitting devices included in the second light source.
 9. The lighting module of claim 1, wherein the base of the first case comprises a first base and a second base, wherein the first case includes an upper case and a lower case, wherein the upper case comprises the first base and the first extension part extending from the first base at a predetermined angle, and wherein the lower case comprises the second base coupled to the first base and the second extension part extending from the second base at a predetermined angle.
 10. The lighting module of claim 9, wherein the first base and the second base comprises a hole or a recess allowing the first base and the second base to be coupled to each other by a coupling means.
 11. The lighting module of claim 1, wherein a ratio of an amount of light emitted through the top surface of the light guide plate to an amount of light emitted through the bottom surface of the light guide plate is from 6:4 to 8:2.
 12. A lighting module of comprising: a light guide plate; a first case coupled to one side of the light guide plate; a light source which is disposed in the first case and emits light to the one side of the light guide plate; a second case coupled to the other side of the light guide plate; and a second light source which is disposed in the second case and emits light to the other side of the light guide plate wherein an amount of light which is emitted through a top surface of the light guide plate is equal to or not equal to an amount of light which is emitted through a bottom surface of the light guide plate, wherein the light guide plate comprises a first light guide plate including a first inclined surface and comprises a second light guide plate including a second inclined surface disposed to face the first inclined surface, and further comprising a reflective plate disposed between the first inclined surface and the second inclined surface, wherein the reflective plate comprises a top surface and a bottom surface and wherein the top and the bottom surfaces of the reflective plate are coated with reflective materials having mutually different reflectances respectively.
 13. The lighting module of claim 12, further comprising a reflective plate, wherein the reflective plate between a first light guide plate and a second light guide plate, wherein the light guide plate comprises the first light guide plate and a second light guide plate disposed below the first light guide plate, wherein the first light source comprises a first upper light source which emits light to one side of the first light guide plate and a first lower light source which emits light to one side of the second light guide plate, and wherein the second light source comprises a second upper light source which emits light to other side of the first light guide plate and a second lower light source which emits light to other side of the second light guide plate.
 14. A lighting module comprising: a first light guide plate; a second light guide plate disposed below the first light guide plate; a reflective plate between the first light guide plate and the second light guide plate; a first and a second light sources which are disposed on both sides of the first light guide plate respectively; a third and a fourth light sources which are disposed on both sides of the second light guide plate respectively; a first case coupled to one side of the first light guide plate and to one side of the second light guide plate; and a second case coupled to the other side of the first light guide plate and to the other side of the second light guide plate, wherein the reflective plate comprises a micro lens.
 15. The lighting module of claim 14, wherein the first and the second light sources comprises warm white light emitting devices and wherein the third and the fourth light sources comprises cool white light emitting devices.
 16. The lighting module of claim 14, wherein a value of current applied to the first and the second light sources is different from a value of current applied to the third and fourth light sources, or wherein a number of light emitting devices included in the first and the second light sources is different from a number of light emitting devices included in the third and fourth light sources.
 17. The lighting module of claim 14, wherein the first light guide plate comprises a first pattern disposed adjacent to the reflective plate, wherein the second light guide plate comprises a second pattern disposed adjacent to the reflective plate, and wherein the first pattern and the second pattern have the same shape or mutually different shapes.
 18. The lighting module of claim 17, wherein the first pattern and the second pattern comprise a plurality of dot patterns, and wherein sizes of the first and the second patterns are different from each other or densities of the first and the second patterns are different from each other.
 19. The lighting module of claim 14, wherein the reflective plate comprises a top surface and a bottom surface and wherein the top and the bottom surfaces of the reflective plate are coated with reflective materials having mutually different reflectances respectively.
 20. The lighting module of claim 14, wherein a plurality of the micro lenses are disposed on a top surface and a bottom surface of the reflective plate respectively, and wherein an interval among the plurality of the micro lenses disposed on the top surface of the reflective plate is different from an interval among the plurality of the micro lenses disposed on the bottom surface of the reflective plate. 